Power management for input/output devices

ABSTRACT

Methods and systems are provided for managing power consumption in network devices. In a network device that may comprise a plurality of ports, each of which being identified by a unique identifier and being adapted to handle separate network traffic, it may be determined whether a first port of the network device may need to be reactivated, where the first port may have been previously shut down by directing of traffic corresponding to the first port, through a virtual port generated on a second port. When the first port is to be reactivated, the virtual port may be turned off, and the first port may then be reactivated. Traffic being routed through the virtual port may be routed before shutting it down; and the paused traffic to and from the network device may be resumed through the first port after it is reactivated.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/731,095, filed Mar. 24, 2010, the entire disclosure of which isincorporated herein by reference in its entirety for all purposes.

FIELD OF THE INVENTION

This invention relates generally to power management in network systemsand more specifically to power management of a network device havingmultiple connections to a network fabric.

BACKGROUND OF THE INVENTION

Power consumption is always a concern in managing an enterprise networksystem. A typical enterprise network, such as a storage network, mayinclude a large number of network devices such as servers, switches, andstorage devices. A number of those devices may be situated in a confinedphysical space. For example, multiple blade servers may be stacked in asingle rack. During operation, electrical and mechanical componentsproduce heat, which must be displaced to ensure proper functioning ofthe server components. In blade enclosures, as in most computingsystems, heat may be removed with fans or reduced by the use of airconditioning. As servers become more powerful, more electricity isconsumed by not only the servers but also the fans and/or the airconditioners needed to keep the servers cool. As such, it is desirableto find ways to reduce the power consumed by each network device withoutjeopardizing the operations of those devices or affecting theirperformance.

SUMMARY OF THE INVENTION

In general, the present invention relates to systems and methods toreduce power consumption of a network device by using virtualizationtechniques to migrate connectivity to a shared port on the networkdevice.

Embodiments of the present invention utilize virtualization techniquesto perform port migration on a network device. The virtualizationtechniques make it possible to encapsulate the characteristics of afirst physical port and, based on the encapsulated characteristics,create a virtual port on a second physical port to perform the samefunctions of the first port. As a result, one or more power-consumingphysical ports can be migrated to a single physical port. Thosepower-consuming ports can then be shut off to save power consumption bythe device without losing any connectivity to other fabric-connecteddevices on the network. When it becomes necessary to switch to apowered-down physical port, or when Input/Output (I/O) bandwidth demandincreases beyond the capacity of the single physical port, the sameencapsulated characteristics can be re-applied to the first ports andthose first ports can be reactivated to provide more bandwidth for thehost server.

In one embodiment, the World Wide Port Name (WWPN) and World Wide NodeName (WWNN) of the first physical port are first noted. Subsequently, anN-Port ID Virtualization (NPIV)—based virtual port on the second port iscreated using the WWPN/WWNN of the first port so that the newly createdvirtual port can assume the identity of the first port. The virtual portmay then be discovered by the host server and log into all theappropriate target storage devices on the network. After theconnectivity between the virtual port and the storage devices isreestablished, I/O traffic to the server is resumed and redirected tothe virtual port. Because the virtual port has adopted the sameWWPN/WWNN as the powered-down first port, the host server would not knowthat the physical communication channels for some of its communicationhas been changed, that a virtual port on the second port, instead of thefirst port, is now being used to connect to target device. As far as theserver is concerned, there has been no change in connectivity to thenetwork. As such, the first physical port can be safely shut downwithout impacting the connectivity of the hosting server.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a conventional Fibre Channelnetwork including a storage device with two dual-port Fibre Channel HostBus Adapters (HBAs).

FIGS. 2 a and 2 b illustrate the connections between an HBA and a fabricswitch before and after port migration has been performed according toan embodiment of the invention.

FIG. 3 is a flow chart illustrating the exemplary steps in migrating aphysical port to another port using virtualization techniques accordingto an embodiment of the invention.

FIG. 4 illustrates a redundant network adapted to utilize the powersaving methods disclosed in embodiments of the invention.

FIG. 5 illustrates an embodiment of a network adapter that may adopt thepower saving methods disclosed in embodiments of the invention.

FIG. 6 illustrates an exemplary host server according to an embodimentof the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following description of preferred embodiments, reference is madeto the accompanying drawings which form a part hereof, and in which itis shown by way of illustration specific embodiments in which theinvention can be practiced. It is to be understood that otherembodiments can be used and structural changes can be made withoutdeparting from the scope of the embodiments of this invention.

In general, the present invention relates to systems and methods toreduce power consumption of a network device by using virtualizationtechniques to migrate connectivity to a shared port on the networkdevice. Although the following embodiments of the invention aredescribed specifically with reference to server-based HBAs, the methodsand systems introduced herein can be extended to hardware environmentsother than those described below. Furthermore, though the embodimentsare described for Fibre Channel networks, it should be understood thatthey can also be adapted for networks using other protocols, such asFibre Channel over Ethernet (FCoE).

FIG. 1 illustrates an exemplary Fibre Channel storage network. The FibreChannel storage network includes a host server 100, a fabric switch 106and two storage devices 108, 110. The host server 100 may be connectedto the storage devices 108, 110 through the fabric switch 106. Althoughonly two storage devices 108, 110 are illustrated, it should beunderstood that additional storage devices may be a part of the networkand connected to the host server 100. The host server 100 includes twodual-port host bus adapters (HBAs) 102, 104. Each of the dual-port HBAs102, 104 has two separate physical Fibre Channel ports (not shown)designed to provide two communication channels to the other devices onthe network. Other networks may use multiple single-port adapters eachwith one physical Fibre Channel port in place of a dual-port HBA.Regardless of what type of HBA is used, each port on the HBAs 102, 104is identifiable by a unique WWPN and/or a WWNN and may be designed to beindependent of one another. In the network illustrated in FIG. 1, thetwo dual-port HBAs 102, 104 may together provide four connections 112 tothe fabric switch 106. Each of these connections may be a full, physicalconnection that utilizes one of the physical FC ports on the HBAs 102,104 and a dedicated optical fiber (or other physical transport means)connecting the HBAs 102, 104 to the fabric switch 106.

The fabric switch 106 may also include multiple ports (not shown)adapted to transmit and receive data from the host server 100. Thefabric switch 106 may be connected to at least one of storage devices108, 110. The fabric switch 106 may effectively determine, by the WWPNsassociated with the ports on the host server 100 and the storage devices108, 110, the connections between the host server 100 and each of thestorage devices 108, 110. Although only one fabric switch 106 isillustrated in FIG. 1, it should be understood that the connectionsbetween the host server 100 and any one of the storage devices 108, 110may go through multiple fabric switches. In other networks, the hostserver may be connected to different storage devices via differentfabric switches.

Because the illustrated host server 100 of FIG. 1 has four separateconnections 112 to the fabric switch 106, power may be continuouslyconsumed by all of the four physical Fibre Channel ports on the two HBAs102, 104 of the server 100 when the server is in operation. Similarly,the corresponding ports on the fabric switch 106 also may always be in apowered-on mode. When the devices are turned on, power may becontinuously consumed regardless of whether or not any of thecommunication channels between the host server and the fabric switch 106are being used to transmit data. That is, not all the bandwidthavailable from all the channels 112 may be needed all the time. In fact,it is very often the case that some channels between the server 100 andthe fabric switch 106 may carry no data at a particular time. Thosechannels may exist for redundancy/failover purposes. In other words,some of the ports (or adapters) are present merely as backups to otherports (or adapters). In other networks, some of the channels may bepresent only for peak demand purposes. During off-peak times, far lessbandwidth than the full available bandwidth is needed by theapplications on the host server 100. This may be the case at night, whenthe usage of the network is typically much lower than during the day.Nevertheless, because all the ports in existing network devices arealways on even when they are not actually in use for transmitting data,the amount of power consumed by the network during off-peak hours maynot be any less than during peak usage.

Because each HBA 102, 104 typically has its own power supply, to theextent that the HBA or portions of the HBAs (e.g., the individual FibreChannel port) can be shut down for a certain period of time when thebandwidth provided by that HBA 102, 104 is not needed, some power may besaved. Accordingly, it may be beneficial to shut down ports that are notcurrently being utilized for carrying data to save power and reduce heatgeneration. However, simply shutting down an adapter or a port on theadapter and dropping the link between that adapter/port and the fabricswitch 106 may not be desirable because it may cause the loss ofconnection to the storage devices connected to the fabric switch 106.This in turn would cause loss of connection to the storage deviceswithin the host server's operating system, creating a ripple effect thatcan yield unpredictable results from the perspective of applicationsrunning on the host server.

Embodiments of the present invention utilize virtualization techniquesto perform port migration on a network device. The virtualizationtechniques make it possible to encapsulate the characteristics of afirst physical port and, based on the encapsulated characteristics,create a virtual port on a second physical port to perform the samefunctions of the first port. As a result, one or more power-consumingphysical ports can be migrated to a single physical port. Thosepower-consuming ports can then be shut off to save power consumption bythe device without losing any connectivity to other fabric-connecteddevices on the network. When it becomes necessary to switch to apowered-down physical port, or when Input/Output (I/O) bandwidth demandincreases beyond the capacity of the single physical port, the sameencapsulated characteristics can be re-applied to the powered-down portsand those powered-down ports can be reactivated to provide morebandwidth for the host server.

FIGS. 2 a and 2 b illustrate, respectively, one of the HBAs of FIG. 1before and after port migration having been performed usingvirtualization techniques. First referring to FIG. 2 a, one of thedual-port HBAs of FIG. 1 is shown in greater detail here. The HBA 102may include two independent physical Fibre Channel ports A and B 202,204. As illustrated in FIG. 2, both physical Fibre Channel ports A and B202, 204 are in a powered-on mode. Each of the physical ports 202, 204has a live connection to the fabric switch 208, through which the hostserver (not shown in FIGS. 2 a and 2 b) housing the HBA is connected toother devices, such as storage devices, on the network. However, asdiscussed previously, one of the physical ports (e.g., port 204) may bea failover for the other port (e.g., port 202). Alternatively, the HBAmay not require the bandwidth provided by both physical ports 202, 204at the same time. Thus, it is desirable to power down one of thephysical ports by migrating the failover/unused physical port 204 to theactive port.

In one embodiment of the invention, virtualization techniques may beused to create a virtual port on a physical port 202 (i.e., the secondport) to take on the role of another physical port 204 (i.e., the firstport) connected to a common fabric. FIG. 2 b illustrates the dual-portHBA 102 of FIG. 2 a having completed a port migration process. Asillustrated in FIG. 2 b, the previously active channel between thesecond Fibre Channel port 204 and the fabric switch 106 has been powereddown. Instead, a virtual instance 206 of the second physical port 204may be created in physical port 202 through a virtualization process,which will be discussed in detail below. The virtual port 206 may sharethe same WWPN/WWNN of the powered-down physical port 204 and perform thetasks that used to be performed by physical port 204. Preferably, thevirtualization process is performed in a way that the host serverhousing the HBA 102 is not aware of the migration of the physical port204 to the virtual port 206 and that the operation of the fabric switch106 is unaffected by the migration. As far as the operating system (OS)and applications on the server are concerned, there has been no changein network connectivity to the rest of the network. Nevertheless,because one of the physical ports 204 has been turned off, electricalpower that is typically required to run that physical port 204 is nolonger needed. Even though the remaining physical port 202, hosting thevirtual port 206, is now responsible for handling all connectivity ofthe HBA 102, it does not require additional power to run. As such, thetotal amount of power consumed by the HBA 102 maybe reduced as a resultof this port migration process.

FIG. 3 illustrates exemplary steps of a method of port migration of afirst physical port to a second physical port. Referring to FIG. 3, thefirst task is to ensure that the first and second ports are connected tothe same fabric switch (step 301). This can be done by verifying theFibre Channel fabric ID of the fabric switch. Next, all input/outputtraffic through the first port (i.e., the physical port to be migrated)is paused (step 302). The duration of the pause is ideally very short(e.g., about a second). After the traffic is cleared, the link betweenthe first port and the fabric switch can be dropped (step 303). In otherembodiments, other actions to reduce the power consumption of the firstport may be additionally or alternatively performed.

As previously mentioned, to keep the connectivity of the host serverintact, a virtual port must be created on the second port to replace thepowered-down first port. The connectivity of the virtual port should beverified so that the host server can function seamlessly during andafter the port migration process. Without the virtual port being readyto take over the connections from the first port, applications on thehost server may encounter serious errors because the host servertypically does not tolerate losing connection to remote devices, whichmay be used to store critical programs and data that the applications onthe server need. Preferably, the migrating process should effectivelycreate a transition to the virtual port in such a way that the OS andapplications on the host server can function as usual without detectingthe transition from the physical port and the virtual port.

According to this embodiment, the WWPN and WWNN of the first physicalport are first noted (step 304). Subsequently, an NPIV-based virtualport on the second port is created using the WWPN/WWNN of the first portso that the newly created virtual port can assume the identity of thefirst port (step 305). The virtual port may then be discovered by thehost server and log into all the appropriate target storage devices onthe network (step 306). After the connectivity between the virtual portand the storage devices is reestablished, I/O traffic to the server isresumed and redirected to the virtual port (step 307). Because thevirtual port has adopted the same WWPN/WWNN as the powered-down firstport, the host server would not know that the physical communicationchannels for some of its communication has been changed, that a virtualport on the second port, instead of the first port, is now being used toconnect to target device. As far as the server is concerned, there hasbeen no change in connectivity to the network. As such, the firstphysical port can be safely shut down without impacting the connectivityof the hosting server. The process can be carried out for other ports onthe same HBA or different HBAs of the server.

Although the migration of one physical port to another physical port isdescribed above, it is to be understood that multiple ports can bemigrated to a single second port in the same way as long as the secondport has enough bandwidth for network traffic. If all physical ports ofone HBA are migrated to one or more physical ports on another HBA, thefirst HBA can be shut off completely. The more physical ports that canbe virtualized on the second port, the more power can be saved byshutting down these physical ports.

In another embodiment, the port to be migrated can itself be a virtualport. The same virtualization technique can be used to migrate one ormore virtual ports on a first physical device (e.g., a first physicalport) to a port of a second physical device. After all of the virtualports of the first physical device are migrated to the second device,the first physical device can be shut off to save power.

As such, according to embodiments of the invention, a tradeoff may bemade between the aggregated bandwidth of the host server and the amountof power that can be saved. The virtualization process discussed in theembodiments can be performed seamlessly, without any significantinterruptions to the operation of the host server. In addition, if thehost server shuts down one of more of its physical ports, thecorresponding ports on the fabric switch can be optionally turned off.That may reduce the power consumption by the fabric switch.

The existence of the virtual port on the second port allows the firstphysical port to be shut down as long as there is sufficient networkbandwidth to handle communication from and to the server. Whenever thedemand for bandwidth increases, the virtual port on the second port canbe shut down and first port can be restarted to provide additionalbandwidth. Basically, the above-described virtualization process in FIG.3 can be reversed. Similarly, if the second port encounters an error andhas to be shut down, the virtual port can be terminated and the firstport can be powered up again to serve as a backup to the second port.According to embodiments of the invention, whenever a physical port isreactivated, the corresponding virtual port may be shut off.

In another aspect of the invention, different methods can be used todetermine when to initiate the above-described port migration process toreduce power consumption. In one embodiment, a time-based algorithm isused where the migration of ports is scheduled at a predetermined time,for example, at midnight when usage of the servers on the network istypically at its lowest level. Knowing that the access rate for I/ooperations is much less at that time of the day, the servers mayautomatically switch the network adapters to a low-power mode byshutting off one or more physical ports on one or more the adapters ofthe servers using virtualization techniques as described above.

In another embodiment, the servers may be running in a power saving mode(i.e., using virtual ports for network connections) unless there is aneed to initiate failover procedures in response to problems with theactive adapter or physical port on which the virtual ports are created.Typical high-availability systems may include multiple hardwarecomponents (e.g., HBAs) and network paths that are redundant. That is,some of the network adapters or ports serve as backups to otheradapters/ports. FIG. 4 illustrates an example of a redundant system. Theredundant system includes four network ports A-D 400, 402, 404, 406, twofabric switches 408, 410, and a storage device 412. The network ports400, 402, 404, 406 may be a part of one or more HBAs or other types ofnetwork cards. Two of the ports (A and C) 400, 404 are active I/o portsconnected to the storage device 412 through fabric switch 408. Ports Band D 402, 406 are failover ports for ports A and C 400, 404,respectively. Both ports B and D 402, 406 are connected to the storagedevice 412 through a second switch 410, which serves as a backup toswitch 408.

As illustrated in FIG. 4, the redundant network ports 400, 402, 404, 406and fabric switches 408, 410 are designed to provide multiple paths tothe storage device 412. For example, if port A 400 fails, its backupport B 402 may be activated and connection to the storage device 412 maybe re-established through port B 402. Similarly, if the connectionbetween active port C 404 and the storage device 412 is interrupted,port D 406, the backup port for port C 404, may be powered up and usedto access the remote storage device 412.

To save power in this type of redundancy setup, one of the failoverports B and D 402, 406 may be shut down and a virtual port 414 may becreated on the remaining failover port (e.g., port B). Thisvirtualization process of the port can be carried out according to theexemplary embodiments described above. The virtual port 414 has theconnectivity and assumes the identity of the turned-off port D 406, andcan still serve as a backup port to port C 404. In this example, port B402 is essentially the only active backup port for both ports A and C400, 404 during normal operation. However, at the command of a failoverapplication, the powered-down physical port D 406 could bere-established to support failover to a separate, redundant physicalport (e.g., port B).

In another embodiment, a prediction-based method can be used to scheduleport migration. In this embodiment, the use of physical ports can becontrolled by an algorithm designed to predict the I/O load based onpast system behavior. In particular, if the I/O load was previouslyrelatively low when the system was in a certain state, port migrationmay be initiated if the same state occurs again.

Some conventional application-specific integrated circuits (ASICs) mayhave mechanisms to shut down portions of its circuit to be able toreduce its overall power consumption. In another aspect of theinvention, an ASIC having multiple ports and adapted to perform thepower-saving port migration process described above is provided. Anyports or other hardware blocks of the ASIC can be shut off to savepower. Given the large number of ASICs that can be found in devices of aconventional network, the potential saving in power consumption can besignificant if the ASIC can be programmed to perform the disclosed portmigration process.

In another aspect of the invention, further power savings can beachieved by controlling the hardware associated with the switch ports.Using the data path that exists between the physical port and the fabricswitch, commands could be transmitted to the fabric switch to instructit to shut down one or more physical ports connected to thenow-powered-down host based ports. Alternatively, the fabric switch canbe instructed to switch to a lower power state (i.e., power saving mode)to reduce power consumption. When the time comes to re-establish thephysical connection, a similar power up command could be used.

Various embodiments of the invention can be implemented in software orfirmware of the device or a combination of both. For example, if portmigration in a particular device is time-based, the timer may be anapplication running on the server. The application has to communicate tothe kernel space where the driver resides. The device driver is anothersoftware entity that controls the operation of the hardware (e.g., anHBA) by instructing the firmware residing in the hardware to carry outthe requisite steps of the virtualization process. In this embodiment,the application is the entity that makes the decision regarding when toinitiate the port migration process. When the scheduled time arrives,the application may issue a command to the driver and, in response, thedriver may issue a command to pause I/O operation in the designatedhardware (e.g., one or more Fibre Channel ports) and then create thevirtual ports on the still active port(s). I/O operation can be resumedafter the virtual port(s) is discovered by the host server. The firmwareassociated with the hardware (e.g., HBA) may be responsible for shuttingdown physical ports to conserve power used by the adapter.

FIG. 5 illustrates another embodiment of an HBA according to embodimentsof the invention. As illustrated, the HBA 900 includes one or moreprocessors 902, a network interface 904, a host bus interface 908, andcomputer readable storage media, such as Random Access Memory (RAM) 906and non-volatile memory 912. The various components of the HBA 900 areall connected to a bus 914 in the HBA 900 and adapted to communicatewith each other using the bus 914. The RAM 912 and the non-volatilememory 906 may be used to store firmware of the HBA 900 and other data.In other embodiments, the firmware may be stored on an externalcomputer-readable storage medium such as a disk and loaded into the HBA900 during operation. The host bus interface 908 connects the HBA 700 toits host via a host bus 910. The network interface 904 provides agateway to an external network.

FIG. 6 illustrates an exemplary host device according to an embodimentof the invention. The host device 1000 includes one or more processors1002, a storage device 1004, a network interface 1010, RAM 1006, andnon-volatile memory 1008. The host device 1000 may also include one ormore device drivers and one or more HBAs (not shown) as described abovein view of FIG. 5. The processor 1002 may execute instructions stored incomputer-readable storage media such as the RAM 1006 and thenon-volatile memory 1008. The storage device 1004 may be a disk capableof storing programs such as firmware for the HBA. The host device isadapted to transmit and receive data from the network using the networkinterface 1010.

Although embodiments of this invention have been fully described withreference to the accompanying drawings, it is to be noted that variouschanges and modifications will become apparent to those skilled in theart. Such changes and modifications are to be understood as beingincluded within the scope of embodiments of this invention as defined bythe appended claims.

1-48. (canceled)
 49. A method, comprising: determining that a first portof a network device needs to be reactivated, wherein the first port isshut down by directing of traffic corresponding to the first port,through a virtual port generated on a second port; turning off thevirtual port; and reactivating the first port.
 50. The method of claim49, comprising pausing traffic being routed through the virtual portbefore shutting it down; and resuming the paused traffic to and from thenetwork device through the first port after it is reactivated.
 51. Themethod of claim 49, comprising determining that the first port is to bereactivated in response to a failover procedure.
 52. The method of claim49, comprising determining that the first port is to be reactivated inresponse to a demand for more bandwidth by the network device.
 53. Themethod of claim 49, comprising determining that the first port is to bereactivated in response to occurrence of error in the second ports withwhich the virtual port is associated.
 54. The method of claim 49,wherein the first and second ports are physical ports.
 55. The method ofclaim 49, wherein the first port is a virtual port on a physical deviceseparate from the second port.
 56. The method of claim 49, wherein thenetwork device is an HBA.
 57. The method of claim 49, wherein thenetwork device is a server and the first and second physical ports aretwo HBAs.
 58. The method of claim 49, wherein the network trafficcomprises communication over a Fibre Channel network or a Fibre Channelover Ethernet network.
 59. The method of claim 49, wherein the portidentifier associated with the first port and a port identifierassociated with the second physical port are the WWPNs of the first andthe second ports, respectively.
 60. The method of claim 49, wherein thefirst port is a part of an ASIC, and wherein the method furthercomprises shutting down part of the ASIC including the first port. 61.The method of claim 49, comprising sending a command to a network endnode associated with the virtual port to activate at least one physicalport corresponding to the first port of the network device.
 62. Anetwork device, comprising: first and a second ports, the network deviceconfigured for: determining that the first port needs to be reactivated,wherein the first port is shut down by directing traffic correspondingto the first port, through a virtual port generated on a second port;turning off the virtual port; and reactivating the first port.
 63. Thenetwork device of claim 62, wherein the network device is furtherconfigured for: pausing traffic being routed through the virtual portbefore shutting it down; and resuming the paused traffic to and from thenetwork device through the first port after it is reactivated.
 64. Thenetwork device of claim 62, wherein the first and second ports arephysical ports.
 65. The network device of claim 62, wherein the firstport is a virtual port on a physical device separate from the secondport.
 66. The network device of claim 62, wherein the first and thesecond ports are ports on an HBA.
 67. The network device of claim 62,wherein the network device is a server and the first and second portsare two HBAs.
 68. The network device of claim 62, wherein the networkdevice is further configured for utilizing Fibre Channel communications.69. The network device of claim 62, wherein the network device isfurther configured for utilizing Fibre Channel over Ethernetcommunications.
 70. The network device of claim 62, wherein the portidentifier associated with the first port and a port identifierassociated with the second physical port are the WWPNs of the first andthe second ports, respectively.
 71. The network device of claim 62,wherein the network device is further configured for determining when toinitiate a power saving mode of the network device.
 72. The networkdevice of claim 62, wherein the network device is hardware associatedwith a switch.
 73. A host server comprising the network device of claim62.
 74. The network device of claim 62, wherein the network device isfurther configured for sending a command to a network end nodeassociated with the virtual port to activate at least one physical portcorresponding to the first port of the network device.
 75. Anon-transitory machine-readable storage medium storing instructionsthat, when executed by one or more processors, cause a machine toperform a method comprising: determining that a first port of a networkdevice needs to be reactivated, wherein the first port is shut down bydirecting of traffic corresponding to the first port, through a virtualport generated on a second port; turning off the virtual port; andreactivating the first port; turning off the virtual port; andreactivating the first port.
 76. The non-transitory machine-readablestorage medium of claim 75, the method further comprising: pausingtraffic being routed through the virtual port before shutting it down;and resuming the paused traffic to and from the network device throughthe first port after it is reactivated.
 77. The non-transitorymachine-readable storage medium of claim 75, wherein the first andsecond ports are physical ports.
 78. The non-transitory machine-readablestorage medium of claim 75, wherein the first port is a virtual port ona physical device separate from the second port.
 79. The non-transitorymachine-readable storage medium of claim 75, wherein the first port andthe second port are adapted to handle separate network traffic.
 80. Thenon-transitory machine-readable storage medium of claim 75, wherein thenetwork traffic comprises communication over a Fibre Channel network ora Fibre Channel over Ethernet network.
 81. The non-transitorymachine-readable storage medium of claim 75, wherein the first and thesecond ports are identified by their respective WWPNs.
 82. Thenon-transitory machine-readable storage medium of claim 75, the methodfurther comprising sending a command to a network end node associatedwith the virtual port to activate at least one physical portcorresponding to the first port of the network device.